Graphene enhanced LiFeBO3/C composites as cathodes for Li-ion batteries

Graphene enhanced LiFeBO3/C composite electrodes are synthesized by a solid-state reaction. The effects of a graphene conductive additive on the LiFeBO3/C electrodes are characterized by XRD, SEM and electrochemical tests. The results show that the electronic conductivities of the LiFeBO3/C electrodes increase with increasing graphene content. The electronic conductivities of the LiFeBO3/C electrodes with Super P (SP) and 5% graphene (5%GN+SP) are 5.16x10(-3) S/cm and 1.65x10(-2) S/cm, respectively. The lithium ion diffusion coefficient (Du) of the LiFeBO3/C electrode with 3% graphene (3%GN+SP) is the highest at 9.85x10(-14) cm(2) s(-1), which is much higher than that of the SP electrode (5.94x10(-14) cm(2) s(-1)). The 3%GN+SP electrode has the highest capacity of 189.6 mAh/g at 0.1 C, and its cyclic retention is 95% after 50 cycles at 1 C. The performance enhancement is mainly attributed to the moderate addition of the graphene conductor, which could improve both the electronic conductivity and ionic diffusion coefficient of the LiFeBO3/C.